Nanowerk March 15, 2023 Perovskites is a promising material for producing 2D monolayer nanosheets if their tunability of bandgap corresponding to the energy of visible light. To solve this problem researchers in Japan focused on a Ruddlesden–Popper (RP) phase layered perovskite oxynitrides and successfully created 2D perovskite oxynitride nanosheets with a tunable bandgap using their novel process. The material had a homogenous thickness of 1.6 nm and exhibited different colors, ranging from white to yellow, depending on the nitridation temperature, and exhibited the semiconductor property of having a tunable bandgap in the visible region, ranging from 2.03-2.63 eV, based on […]
Tag Archives: S&T Japan
Neural networks could help predict destructive earthquakes
Phys.org March 3, 2023 The movement and deformation of the Earth’s crust and upper mantle provide critical insights into the evolution of earthquake processes and future earthquake potentials. Crustal deformation can be modeled by dislocation models that represent earthquake faults in the crust as defects in a continuum medium. Researchers in Japan have proposed a physics-informed deep learning approach to model crustal deformation due to earthquakes. Neural networks can represent continuous displacement fields in arbitrary geometrical structures and mechanical properties of rocks by incorporating governing equations and boundary conditions into a loss function. They introduced polar coordinate system to accurately […]
Scientists thread rows of metal atoms into nanofiber bundles
Phys.org March 6, 2023 A class of 3D atomic wires of transition metal chalcogenides (TMC) structures consisting of bundles of TMC nanofibers held together by metallic atoms in between the fibers, all forming a well-ordered lattice in its cross section are of particular interest. Depending on the choice of metal, the structure could even be made to become a superconductor. Researchers in Japan demonstrated versatile method to fabricate indium (In)-intercalated W6Te6 (In–W6Te6) bundles with a nanoscale thickness. Atomic-resolution electron microscopy revealed that In atoms were surrounded by three adjacent W6Te6 wires. First-principles calculations suggested that their wire-by-wire stacking can transform […]
Fickle winters in East Asia caused by major shift in regional atmospheric circulation, suggests study
Phys.org February 27, 2023 Researchers in Japan investigated the structure and dynamics of two distinct patterns. They showed that the winter climate over East Asia is influenced by two teleconnection patterns, the western Pacific pattern, and the Southeast Asia-Japan pattern. Using meteorological data for winters from 1974 to 2021 they established the baseline climate and analyzed anomalous departures from that baseline. In the first half of the 2020/2021 winter season, an anticyclonic circulation anomaly appeared over the southeastern Tibetan Plateau, and a corresponding cyclonic anomaly occurred over northern Japan. This pattern was associated with enhanced convection over the South China […]
Improving the performance of satellites in low Earth orbit
EurekAlert February 21, 2023 Although small satellites have a lot of potential due to their smaller size, they have lesser radiation shield and the deployable membrane attached to the main body for a large phased-array transceiver causing non-uniform radiation degradation across the transceiver. This affects the gain variation and performance of the satellite. To mitigate radiation degradation researchers in Japan created a phased-array transceiver with on-chip distributed radiation sensors which can detect the gain variation between the chips of the antenna. This was combined with current-sharing techniques to mitigate the gain variation and thus reduce the impact of non-uniform ionizing […]
Solid material that ‘upconverts’ visible light photons to UV light photons could change how we utilize sunlight
Phys.org January 30, 2023 Only about 4% of terrestrial sunlight falls within the UV range in the electromagnetic spectrum. This leaves a large portion of sunlight spectrum unexploited for photopolymerization to form a resin and activation of photocatalysts to drive reactions that generate green hydrogen or useful hydrocarbons (fuels, sugars, olefins, etc.). Photon upconversion (UC) could be the key to solving this problem. Researchers in Japan have developed a revolutionary solid film that can perform visible-to-UV photon UC for weak incident light while remaining photostable for an unprecedented amount of time in air. The film is completely solvent-free “green” formation […]
Recreating the natural light-harvesting nanorings in photosynthetic bacteria
Science Daily January 31, 2023 Photosynthesis in plants and some bacteria relies on light-harvesting (LH) supramolecules which come in different structures. So far, these LH molecules have not been artificially prepared. Researchers in Japan demonstrated that mixing a chlorophyll derivative with naphthalenediamide in an organic solvent leads to the formation of dimers that spontaneously self-assembled into ring-shaped structures, each several hundred nanometers in diameter. They observed that chlorophyll dimers, molecules composed of two chlorophyll units linked by naphthalene, initially self-assembled into stable wavy nanofibers. Upon heating these nanofibers at 50°C, they disassembled into smaller nanoring precursors whose ends eventually joined […]
Topological acoustic waveguide to help reduce unwanted energy consumption in electronics
Pays.org January 30, 2023 Researchers in Japan have shown that in a honeycomb phononic crystal composed of metallic nanopillars on a LiNbO3 substrate, the topological surface acoustic wave (SAW) mode inhabits the edge of the honeycomb phononic crystal in spite of the hybridization with the internal acoustic modes of the substrate. Pulse-type microwave impedance microscopy showed gigahertz topological edge mode between two mutually inverted topological phononic crystals. A frequency-dependent image showed that the edge mode evolves as the bulk SAW modes are suppressed owing to the energy gap formation, consistent with the topological nature. According to researchers the realization of a […]
Electronic nose: Sensing the odor molecules on graphene surface layered with self-assembled peptides
Science Daily January 19, 2023 Researchers in Japan designed and developed three new peptides for graphene biosensors that can detect odor molecules to perform two main functions — acting as a biomolecular scaffold for self-assembly on a graphene surface and functioning as a bio-probe to bind the odor molecules. They showed that the peptides uniformly covered the graphene surface with the thickness of a single molecule. When representative odor molecules were injected into the functionalized graphene field-effect transistors (GFETs), graphene conductivity reduced indicating the binding of the odor molecules. The odor molecules gave rise to distinct signatures confirming that the […]
GHz burst mode femtosecond laser pulses can create unique two-dimensional periodic surface nanostructures
Phys.org January 24, 2023 Most studies using the GHz burst mode femtosecond laser pulses focus on ablation of materials to achieve high-efficiency and high-quality material removal. Researchers in Japan explored the ability of the GHz burst mode femtosecond laser processing to form laser-induced periodic surface structures (LIPSS) on silicon. The direction of LIPSS formed by the single-pulse mode with linearly polarized laser pulses is typically perpendicular to the laser polarization direction. They showed that the GHz burst mode femtosecond laser created unique two-dimensional LIPSS. The team has proposed a possible mechanism for the formation of 2D LIPSS formed by the […]